As is already known, beast wool represented by sheep wool is passed through many processes including the washing of raw wool before it is finally used as fiber products in daily life. Particularly, chemical treatments such as scouring, bleaching, dyeing, shrink resistance and the like are inevitable.
For example, the bleaching of wool fibers is generally carried out by an oxidation bleaching method in which the fibers are treated in a bleaching bath containing an oxidizing agent represented by hydrogen peroxide as an active ingredient, or by a reduction bleaching method in which they are treated in a bleaching bath containing a reducing agent represented by hydrosulfite as an active ingredient.
Wool fibers which are bleached by oxidation are then often bleached again as the after-treatment using a bath containing a thionite-type reducing agent such as hydrosulfite, thiourea dioxide or the like for the purpose of improving their whiteness.
In recent years, an increasing number of textile goods made of wool which are with beads or metallic accessories have been on the market. Such textile goods, however, have the problem that sulfuric gases are generated from traces of reducing agent which remain in the wool and which is used at the after-treatment while they are stored in plastic bags or displayed in the show window, resulting in discoloration of the beads of pearl color to a dark color within 1 or 2 months.
Wool shrinks during processing or during the washing of the processed products owing to the characteristics of the wool structure. Thus, wool may often be treated for shrink resistance.
For example, shrinkproofing of wool fibers is generally treated by adding them in a bath of aqueous solution containing, as an active ingredient, such an agent as chlorinated isocyanurate, potassium permanganate, a peroxide or the like.
Such shrinkresist treatment using the above-described agent for shrinkresistance is, however, generally carried out before dyeing; it is very difficult to carry out shrinkresistance of wool after dyeing as the process may cause discoloring, fading or decoloring of the dyed product or degradation of the wool. When the treatment for shrinkresistance is applied to the dyed wool, therefore, the shrinkresist treatment of conventional methods can not be applied.
The shrinkresistance using the above-described agent involves the problem that the processing conditions are very strict and the control of the bath is very difficult. It is impossible to impart pilling resistance and shrinkresistance to wool simultaneously by conventional methods.
Dyeing of wool fibers is generally carried out by a high-temperature dyeing method (boiling point dyeing method) which uses a dyeing bath prepared in the following manner. Dyes and some acid such as sulfuric acid, acetic acid, formic acid or the like, some salt such as ammonium sulfate, ammonium acetate or the like, Glauber's salt and some leveling agent or the like are added in dyeing bath. This brings the dyeing bath within the weak acid region or the acid region. The temperature of the dyeing bath is gradually raised from the room temperature to the boiling point and then held at the boiling point for about 60 minutes.
Then, since such a high temperature dyeing method easily degrades the fibrous tissues of wool, low-temperature dyeing methods such as a urea method, a formic acid method, a surfactant method and an organic solvent method in which a dyeing bath is not heated to the boiling point thereof but kept at the lower temperature below the boiling point are now being investigated for the protection of wool fiber quality. Attempts which are made to subject wool suitable for low-temperature dyeing to processing using a bath containing, as an active ingredient, an organic phosphine compound are reported in J, Soc. Dyers & Colourists, Vol. 95, 396, Aust. J. Chem., Vol. 19, 2347-2360 (1966), and Aust. J. Biol. Sci., Vol. 21, 805-813 (1968). Although such a bath is prepared by dissolving tributylphosphine in an aqueous solution of propanol, tributylphosphine is water-insoluble. Thus a water-soluble organic phosphine compound related to the present invention is different from the insoluble compound.
The above-described conventional after treatment subsequent to oxidation bleaching in chemical processing makes it impossible to prevent discoloration of the beads or metallic accessories on wool with the passage of time.
The conventional high-temperature dyeing method also has a disadvantage of degrading wool making it, brittle and inferior in handling touch. But the low-temperature dyeing method has never been achieved in the technical aspect in spite of efforts, and substantially no method has been put into practical use in the industrial field.
As a result of energetic research on processing and treating of wool fibers conducted by the inventors with a view to solving the above-described problem, it was found that the use of an agent containing as an active ingredient a water-soluble organic phosphine compound exhibits significant improvements, particularly, improvement in pilling resistance and that it enables processed wool products of good quality to be obtained. This leads to the achievement of the present invention.